Fig. 4
From: Circles reshaping the RNA world: from waste to treasure
Five main functions of circRNA. Legend: CircRNAs possess five main functions which have been validated in some related researches. 1. MiRNA sponge: circRNAs serve as the platform to bind miRNAs and affect their biological function, regulating the activity of miRNA-target gene. 2. Post-transcription regulation: the stable ciRNA and EIciRNA locate in nucleus, binding to elongating RNA Pol II and promoting transcription. 3. Rolling Circle Translation: some circRNAs can translate into proteins via a rolling circle amplification mechanism, while only the vitro circRNA till date has been verified to encode proteins in eukaryotic cells. 4. Generating the circRNA-derived pseudogenes: some circRNAs may be reversely transcribed to cDNA and integrated into the genome based on an unknown way. 5. Affects alternative splicing: circRNA biogenesis can compete with pre-mRNA splicing, resulting in lower levels of linear mRNAs and changing the composition of processed mRNA by excluding specific exons from the pre-mRNA